whisper_library::LengthCoder Class Reference

Converts between messages and packet lengths (used by PacketLengthCovertChannel) More...

Public Member Functions
	LengthCoder (int baselength)
	Constructor of LengthCoder. More...
std::vector< unsigned int >	encodeMessage (std::string message)
	encodes a message to packet lengths More...
std::string	decodeMessage (std::vector< unsigned int > lengths)
	decodes packet lengths More...

Private Attributes
int	m_baselength
	gets added/substracted from the packet lengths

Detailed Description

Converts between messages and packet lengths (used by PacketLengthCovertChannel)

A LengthCoder can be used to encode messages into udp packet lengths and decode udp packet lengths into a message. A base length/offset for the packet lengths can be set to avoid packets with no data payload (length = 8).

The LengthCoder uses the BitSetCoder to split the message into parts

See Also

BitSetCoder

Constructor & Destructor Documentation

whisper_library::LengthCoder::LengthCoder ( int  baselength )

inline

Constructor of LengthCoder.

Creates an LengthCoder and sets the base length, which is added to every packet length

Parameters

baselength

length offset for every packet

Member Function Documentation

std::string whisper_library::LengthCoder::decodeMessage

(

std::vector< unsigned int >

lengths

)

decodes packet lengths

The lengths from the given vector get decoded into a string. The lengths should be between baseLength and baseLength + 15

Parameters

lengths

a vector containing received udp packet lengths

Returns

a string with the decoded message

std::vector< unsigned int > whisper_library::LengthCoder::encodeMessage

(

std::string

message

)

encodes a message to packet lengths

The given message gets translated to packet lengths variing from baseLength to baseLength + 15.

Parameters

message

the message that gets encoded

Returns

an vector containing udp packet Length in the range of baseLength to baseLength + 15.